1 files changed, 49 insertions, 0 deletions
diff --git a/2024/02/puzzles.awk b/2024/02/puzzles.awk
new file mode 100644
index 0000000..789a193
--- /dev/null
+++ b/2024/02/puzzles.awk
@@ -0,0 +1,49 @@
+#!/usr/bin/gawk -f
+
+function sign(x)
+{
+	return x < 0 ? -1 : +1
+}
+
+function abs(x)
+{
+	return x < 0 ? -x : x
+}
+
+function check(skip,    xs, s, i, j, d, D)
+{
+	for (i = 1; i <= NF; i++) {
+		if (i != skip)
+			xs[++j] = $i
+	}
+	s = sign(xs[1] - xs[2])
+	for (i = 2; i <= length(xs); i++) {
+		d = xs[i - 1] - xs[i]
+		D = abs(d)
+		if (sign(d) != s || D < 1 || D > 3)
+			return 0
+	}
+	return 1
+}
+
+# START PART 1
+{
+	s = sign($1 - $2)
+	n += check()
+}
+# END PART 1 START PART 2
+{
+	s = sign($1 - $2)
+	if (!check()) {
+		for (i = 1; i <= NF; i++) {
+			if (check(i))
+				break
+		}
+		if (i > NF)
+			next
+	}
+	n++
+}
+# END PART 2
+
+END { print n }
+\ No newline at end of file